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Sharma H, Azouz R. Global and local neuronal coding of tactile information in the barrel cortex. Front Neurosci 2024; 17:1291864. [PMID: 38249584 PMCID: PMC10796699 DOI: 10.3389/fnins.2023.1291864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Accepted: 11/24/2023] [Indexed: 01/23/2024] Open
Abstract
During tactile sensation in rodents, the whisker movements across surfaces give rise to intricate whisker motions that encompass discrete and transient stick-slip events, effectively conveying valuable information regarding surface properties. These surface characteristics are transformed into cortical neuronal responses. This study examined the coding strategies underlying these transformations in rat whiskers. We found that changes in surface coarseness modified the number and magnitude of stick-slip events, which in turn both modulated properties of neuronal responses. Global changes in the number of stick-slip events primarily affected neuronal discharge rates and the degree of neuronal synchronization. In contrast, local changes in the magnitude of stick-slip events affected the transformation of these kinematic and kinetic characteristics into neuronal discharges. Most cortical neurons exhibited surface coarseness selectivity through global and local stick-slip event properties. However, this selectivity varied across coding strategies in the same neurons, given that each coding strategy reflected different aspects of changes in whisker-surface interactions. The degree of spatial similarity in surface coarseness preference in adjacently recorded neurons differed among these coding strategies. Adjacently recorded neurons exhibited the same surface coarseness preference in their firing rates but not through other coding strategies. Through these results, we were able to show that local stick-slip event properties contribute to texture discrimination, complementing and surpassing global coding in this context. These findings suggest that the representation of surface coarseness in the cortex may rely on concurrent coding strategies that integrate tactile information across different spatiotemporal scales.
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Affiliation(s)
| | - Rony Azouz
- Department of Physiology and Cell Biology, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Be'er Sheva, Southern District, Israel
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2
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Dai J, Sun QQ. Learning induced neuronal identity switch in the superficial layers of the primary somatosensory cortex. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.30.555603. [PMID: 37693620 PMCID: PMC10491147 DOI: 10.1101/2023.08.30.555603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
During learning, multi-dimensional inputs are integrated within the sensory cortices. However, the strategies by which the sensory cortex employs to achieve learning remains poorly understood. We studied the sensory cortical neuronal coding of trace eyeblink conditioning (TEC) in head-fixed, freely running mice, where whisker deflection was used as a conditioned stimulus (CS) and an air puff to the cornea delivered after an interval was used as unconditioned stimulus (US). After training, mice learned the task with a set of stereotypical behavioral changes, most prominent ones include prolonged closure of eyelids, and increased reverse running between CS and US onset. The local blockade of the primary somatosensory cortex (S1) activities with muscimol abolished the behavior learning suggesting that S1 is required for the TEC. In naive animals, based on the response properties to the CS and US, identities of the small proportion (~20%) of responsive primary neurons (PNs) were divided into two subtypes: CR (i.e. CS-responsive) and UR neurons (i.e. US-responsive). After animals learned the task, identity of CR and UR neurons changed: while the CR neurons are less responsive to CS, UR neurons gain responsiveness to CS, a new phenomenon we defined as 'learning induced neuronal identity switch (LINIS)'. To explore the potential mechanisms underlying LINIS, we found that systemic and local (i.e. in S1) administration of the nicotinic receptor antagonist during TEC training blocked the LINIS, and concomitantly disrupted the behavior learning. Additionally, we monitored responses of two types of cortical interneurons (INs) and observed that the responses of the somatostatin-expressing (SST), but not parvalbumin-expressing (PV) INs are negatively correlated with the learning performance, suggesting that SST-INs contribute to the LINIS. Thus, we conclude that L2/3 PNs in S1 encode perceptual learning by LINIS like mechanisms, and cholinergic pathways and cortical SST interneurons are involved in the formation of LINIS.
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Affiliation(s)
- Jiaman Dai
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY82071, USA
- Wyoming Sensory Biology Center of Biomedical Research Excellence, University of Wyoming, Laramie, WY82071, USA
| | - Qian-Quan Sun
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY82071, USA
- Wyoming Sensory Biology Center of Biomedical Research Excellence, University of Wyoming, Laramie, WY82071, USA
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3
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Ding Y, Vlasov Y. Pre-neuronal processing of haptic sensory cues via dispersive high-frequency vibrational modes. Sci Rep 2023; 13:14370. [PMID: 37658126 PMCID: PMC10474056 DOI: 10.1038/s41598-023-40675-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2023] [Accepted: 08/16/2023] [Indexed: 09/03/2023] Open
Abstract
Sense of touch is one of the major perception channels. Neural coding of object textures conveyed by rodents' whiskers has been a model to study early stages of haptic information uptake. While high-precision spike timing has been observed during whisker sweeping across textured surfaces, the exact nature of whisker micromotions that spikes encode remains elusive. Here, we discovered that a single micro-collision of a whisker with surface features generates vibrational eigenmodes spanning frequencies up to 10 kHz. While propagating along the whisker, these high-frequency modes can carry up to 80% of shockwave energy, exhibit 100× smaller damping ratio, and arrive at the follicle 10× faster than low frequency components. The mechano-transduction of these energy bursts into time-sequenced population spike trains may generate temporally unique "bar code" with ultra-high information capacity. This hypothesis of pre-neuronal processing of haptic signals based on dispersive temporal separation of the vibrational modal frequencies can shed light on neural coding of haptic signals in many whisker-like sensory organs across the animal world as well as in texture perception in primate's glabrous skin.
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Affiliation(s)
- Yu Ding
- Department of Physics, University of Illinois Urbana Champaign, 208 North Wright Street, Urbana, IL, 61801, USA
| | - Yurii Vlasov
- Department of Physics, University of Illinois Urbana Champaign, 208 North Wright Street, Urbana, IL, 61801, USA.
- Department of BioEngineering, University of Illinois Urbana Champaign, 208 North Wright Street, Urbana, IL, 61801, USA.
- Carle Illinois College of Medicine, University of Illinois Urbana Champaign, 208 North Wright Street, Urbana, IL, 61801, USA.
- Department of Electrical and Computer Engineering, University of Illinois Urbana Champaign, 208 North Wright Street, Urbana, IL, 61801, USA.
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4
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Barbosa IR, da Cunha G, Luft C, Rübensam G, Freitas RDS, Greggio S, Venturin G, de Oliveira JR, da Costa JC, Campos MM. Fructose supplementation shifts rat brain metabolism in experimental migraine. Brain Res Bull 2023:110694. [PMID: 37353036 DOI: 10.1016/j.brainresbull.2023.110694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 05/28/2023] [Accepted: 06/20/2023] [Indexed: 06/25/2023]
Abstract
AIMS We have previously demonstrated that fructose supplementation (FS), given in a scheme used for inducing metabolic syndrome (MS), elicited pain relief in the nitroglycerin (NTG)-elicited rat migraine model. Herein, we evaluated whether FS could reestablish the impaired metabolic pathways in NTG-injected rats. MAIN METHODS Male Wistar rats (N=40) were divided into two groups for receiving 10-% FS or tap water. After 45 days, they were subdivided into NTG-injected (10mg/kg; 15 days) or controls. After the fourth NTG injection, 18F-fluorodeoxyglucose ([18F] FDG) micro-PET scanning was accomplished. The day after, euthanasia was performed, and blood was collected for glycemia and LDH analysis. The levels of energy molecules, TBARS, PGC-1α, and MCTS1 were evaluated in the brain cortices. The activated satellite glial cells (SGC) were assessed in the trigeminal ganglion (TG). KEY FINDINGS There were no variations of glycemia or LDH serum levels. NTG-injected rats showed a significant increase in glucose uptake in the hypothalamus (HT) vs. NTG-free rats. The FS-NTG group showed increased metabolism in the superior colliculus (SC) vs. the NTG group. Moreover, the glucose uptake was amplified in the inferior colliculus (IC) of the FS-NTG vs. FS group. The cortical inosine levels were significantly higher in FS-NTG rats vs. NTG or FS groups, with no changes in TBARS or MCTS1 levels, despite a minor decrease of PGC1-α contents in the FS+NTG group. Finally, there was a significant increase of activated SGC around TG in the FS-NTG rats. SIGNIFICANCE We provide novel evidence linking nutrition and metabolism with migraine.
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Affiliation(s)
- Isadora R Barbosa
- PUCRS, Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Porto Alegre/RS, Brasil; PUCRS, Curso de Graduação em Odontologia, Escola de Ciências da Saúde e da Vida, Porto Alegre/RS, Brasil
| | - Gabriela da Cunha
- PUCRS, Curso de Graduação em Odontologia, Escola de Ciências da Saúde e da Vida, Porto Alegre/RS, Brasil; PUCRS, Centro de Pesquisa em Toxicologia e Farmacologia, Escola de Ciências da Saúde e da Vida, Porto Alegre/RS, Brasil
| | - Carolina Luft
- PUCRS, Laboratório de Pesquisa em Biofísica Celular e Inflamação, Escola de Ciências da Saúde e da Vida Porto Alegre, Brazil
| | - Gabriel Rübensam
- PUCRS, Centro de Pesquisa em Toxicologia e Farmacologia, Escola de Ciências da Saúde e da Vida, Porto Alegre/RS, Brasil
| | - Raquel D S Freitas
- PUCRS, Centro de Pesquisa em Toxicologia e Farmacologia, Escola de Ciências da Saúde e da Vida, Porto Alegre/RS, Brasil; PUCRS, Programa de Pós-Graduação em Medicina e Ciências da Saúde, Escola de Ciências da Saúde e da Vida, Porto Alegre/RS, Brasil
| | - Samuel Greggio
- PUCRS, Curso de Graduação em Biomedicina, Escola de Ciências da Saúde e da Vida, Porto Alegre/RS, Brasil
| | - Gianina Venturin
- PUCRS, Centro de Pesquisa Pré-clínica, Instituto do Cérebro (BraIns), Porto Alegre/RS, Brazil
| | - Jarbas R de Oliveira
- PUCRS, Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Porto Alegre/RS, Brasil; PUCRS, Laboratório de Pesquisa em Biofísica Celular e Inflamação, Escola de Ciências da Saúde e da Vida Porto Alegre, Brazil; PUCRS, Programa de Pós-Graduação em Medicina e Ciências da Saúde, Escola de Ciências da Saúde e da Vida, Porto Alegre/RS, Brasil
| | - Jaderson C da Costa
- PUCRS, Programa de Pós-Graduação em Medicina e Ciências da Saúde, Escola de Ciências da Saúde e da Vida, Porto Alegre/RS, Brasil; PUCRS, Centro de Pesquisa Pré-clínica, Instituto do Cérebro (BraIns), Porto Alegre/RS, Brazil; PUCRS, Laboratório de Neurociências e Eletrofisiologia, Porto Alegre/RS, Brasil
| | - Maria M Campos
- PUCRS, Programa de Pós-Graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Porto Alegre/RS, Brasil; PUCRS, Curso de Graduação em Odontologia, Escola de Ciências da Saúde e da Vida, Porto Alegre/RS, Brasil; PUCRS, Centro de Pesquisa em Toxicologia e Farmacologia, Escola de Ciências da Saúde e da Vida, Porto Alegre/RS, Brasil; PUCRS, Programa de Pós-Graduação em Medicina e Ciências da Saúde, Escola de Ciências da Saúde e da Vida, Porto Alegre/RS, Brasil.
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5
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The role of sensory feedback from carpal sinus hairs in locomotor kinematics of rats (Rattus norvegicus, Rodentia) during walking on narrow substrates. ZOOLOGY 2022; 155:126055. [PMID: 36423499 DOI: 10.1016/j.zool.2022.126055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 10/10/2022] [Accepted: 10/24/2022] [Indexed: 11/06/2022]
Abstract
Carpal sinus hairs on the forearms are assumed to have evolved within the stem lineage of Theria. The presence and similar position of these specialized tactile hairs in scansorial and terrestrial species as well as earlier studies on rats indicate a biological role in sensing substrate irregularities in high structured environments to ensure the dynamic stability of the body during locomotion. While these sensors were considered as one functional unit until so far, the present study deals with the biological role of the single tactile hairs of the trident, assuming a role in sensing substrate diameters and adapting limb coordination and body posture to different arboreal inclinations. To investigate the influence of each hair, we studied the locomotion of rats on poles of two different diameters whereby we selectively removed individual carpal sinus hairs. The rats walked at speeds ranging from 0.12 m/s to 0.58 m/s. Normal-light high-speed cameras and x-ray fluoroscopy visualized the hairs and body dynamics during locomotion. The time lag between first contact of the hairs to the branch until contact of the forepaw was 56-108 ms. Within this time window the pronation/supination of the paw and anterior body posture are adjusted to the substrate diameter. We presume that the most proximal sinus hair (located between the medial and lateral one) senses the paw-substrate distance through the increasing bend from its first branch-contact until the contact of the paw. The medial and the lateral hairs touch the pole sides and thereby, may collect information about the properties of the small-diameter substrate. The removal of single hairs from the group results in minor changes of kinematic parameters, but locomotor stability is seriously impaired when more than one hair is cut. The kinematic responses span from a more crouched body posture and higher forearm pronation to paw slipping, muscle tremor or complete refusal to walk on the narrow substrate.
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6
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Sharma H, Azouz R. Coexisting neuronal coding strategies in the barrel cortex. Cereb Cortex 2022; 32:4986-5004. [PMID: 35149866 DOI: 10.1093/cercor/bhab527] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 12/19/2021] [Accepted: 12/20/2021] [Indexed: 12/27/2022] Open
Abstract
During tactile sensation by rodents, whisker movements across surfaces generate complex whisker motions, including discrete, transient stick-slip events, which carry information about surface properties. The characteristics of these events and how the brain encodes this tactile information remain enigmatic. We found that cortical neurons show a mixture of synchronized and nontemporally correlated spikes in their tactile responses. Synchronous spikes convey the magnitude of stick-slip events by numerous aspects of temporal coding. These spikes show preferential selectivity for kinetic and kinematic whisker motion. By contrast, asynchronous spikes in each neuron convey the magnitude of stick-slip events by their discharge rates, response probability, and interspike intervals. We further show that the differentiation between these two types of activity is highly dependent on the magnitude of stick-slip events and stimulus and response history. These results suggest that cortical neurons transmit multiple components of tactile information through numerous coding strategies.
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Affiliation(s)
- Hariom Sharma
- Department of Physiology and Cell Biology, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Rony Azouz
- Department of Physiology and Cell Biology, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer Sheva, Israel
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7
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Connectomic analysis of thalamus-driven disinhibition in cortical layer 4. Cell Rep 2022; 41:111476. [DOI: 10.1016/j.celrep.2022.111476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 07/29/2022] [Accepted: 09/19/2022] [Indexed: 11/18/2022] Open
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8
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Physiological noise facilitates multiplexed coding of vibrotactile-like signals in somatosensory cortex. Proc Natl Acad Sci U S A 2022; 119:e2118163119. [PMID: 36067307 PMCID: PMC9478643 DOI: 10.1073/pnas.2118163119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Neurons can use different aspects of their spiking to simultaneously represent (multiplex) different features of a stimulus. For example, some pyramidal neurons in primary somatosensory cortex (S1) use the rate and timing of their spikes to, respectively, encode the intensity and frequency of vibrotactile stimuli. Doing so has several requirements. Because they fire at low rates, pyramidal neurons cannot entrain 1:1 with high-frequency (100 to 600 Hz) inputs and, instead, must skip (i.e., not respond to) some stimulus cycles. The proportion of skipped cycles must vary inversely with stimulus intensity for firing rate to encode stimulus intensity. Spikes must phase-lock to the stimulus for spike times (intervals) to encode stimulus frequency, but, in addition, skipping must occur irregularly to avoid aliasing. Using simulations and in vitro experiments in which mouse S1 pyramidal neurons were stimulated with inputs emulating those induced by vibrotactile stimuli, we show that fewer cycles are skipped as stimulus intensity increases, as required for rate coding, and that intrinsic or synaptic noise can induce irregular skipping without disrupting phase locking, as required for temporal coding. This occurs because noise can modulate the reliability without disrupting the precision of spikes evoked by small-amplitude, fast-onset signals. Specifically, in the fluctuation-driven regime associated with sparse spiking, rate and temporal coding are both paradoxically improved by the strong synaptic noise characteristic of the intact cortex. Our results demonstrate that multiplexed coding by S1 pyramidal neurons is not only feasible under in vivo conditions, but that background synaptic noise is actually beneficial.
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9
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Buetfering C, Zhang Z, Pitsiani M, Smallridge J, Boven E, McElligott S, Häusser M. Behaviorally relevant decision coding in primary somatosensory cortex neurons. Nat Neurosci 2022; 25:1225-1236. [PMID: 36042310 PMCID: PMC7613627 DOI: 10.1038/s41593-022-01151-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 07/21/2022] [Indexed: 11/20/2022]
Abstract
Primary sensory cortex is thought to process incoming sensory information, while decision variables important for driving behavior are assumed to arise downstream in the processing hierarchy. Here, we used population two-photon calcium imaging and targeted two-photon optogenetic stimulation of neurons in layer 2/3 of mouse primary somatosensory cortex (S1) during a texture discrimination task to test for the presence of decision signals and probe their behavioral relevance. Small but distinct populations of neurons carried information about the stimulus irrespective of the behavioral outcome (stimulus neurons), or about the choice irrespective of the presented stimulus (decision neurons). Decision neurons show categorical coding that develops during learning, and lack a conclusive decision signal in Miss trials. All-optical photostimulation of decision neurons during behavior improves behavioral performance, establishing a causal role in driving behavior. The fact that stimulus and decision neurons are intermingled challenges the idea of S1 as a purely sensory area, and causal perturbation suggests a direct involvement of S1 decision neurons in the decision-making process.
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Affiliation(s)
- Christina Buetfering
- Wolfson Institute for Biomedical Research and Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK.
- Institute of Pathophysiology, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany.
| | - Zihui Zhang
- Wolfson Institute for Biomedical Research and Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
- Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, CA, USA
| | - Margarita Pitsiani
- Wolfson Institute for Biomedical Research and Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - John Smallridge
- Wolfson Institute for Biomedical Research and Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
- Neurophenomenology of Consciousness Laboratory, Department of Psychiatry, Psychotherapy and Psychosomatics, Psychiatric Hospital, University of Zurich, Zurich, Switzerland
| | - Ellen Boven
- Wolfson Institute for Biomedical Research and Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
- School of Physiology, Pharmacology and Neuroscience, Faculty of Life Sciences, University of Bristol, Bristol, UK
| | - Sacha McElligott
- Wolfson Institute for Biomedical Research and Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Michael Häusser
- Wolfson Institute for Biomedical Research and Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK.
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10
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Lemercier CE, Krieger P. Reducing Merkel cell activity in the whisker follicle disrupts cortical encoding of whisker movement amplitude and velocity. IBRO Neurosci Rep 2022; 13:356-363. [PMID: 36281438 PMCID: PMC9586890 DOI: 10.1016/j.ibneur.2022.09.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 09/26/2022] [Indexed: 11/26/2022] Open
Abstract
Merkel cells (MCs) and associated primary sensory afferents of the whisker follicle-sinus complex, accurately code whisker self-movement, angle, and whisk phase during whisking. However, little is known about their roles played in cortical encoding of whisker movement. To this end, the spiking activity of primary somatosensory barrel cortex (wS1) neurons was measured in response to varying the whisker deflection amplitude and velocity in transgenic mice with previously established reduced mechanoelectrical coupling at MC-associated afferents. Under reduced MC activity, wS1 neurons exhibited increased sensitivity to whisker deflection. This appeared to arise from a lack of variation in response magnitude to varying the whisker deflection amplitude and velocity. This latter effect was further indicated by weaker variation in the temporal profile of the evoked spiking activity when either whisker deflection amplitude or velocity was varied. Nevertheless, under reduced MC activity, wS1 neurons retained the ability to differentiate stimulus features based on the timing of their first post-stimulus spike. Collectively, results from this study suggest that MCs contribute to cortical encoding of both whisker amplitude and velocity, predominantly by tuning wS1 response magnitude, and by patterning the evoked spiking activity, rather than by tuning wS1 response latency. The role of Merkel cells (MCs) in cortical encoding of whisker deflection amplitude and velocity was investigated. Reducing MC synaptic activity increased barrel cortex neurons response sensitivity to whisker deflection. This effect occurred from a lack of variation in response magnitude to varying whisker deflection amplitude and velocity. However, stimuli differentiation through changes in cortical response latency was preserved. MCs are thus suggested to play a predominant role in tuning the cortical response magnitude over the response latency.
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11
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Adibi M, Lampl I. Sensory Adaptation in the Whisker-Mediated Tactile System: Physiology, Theory, and Function. Front Neurosci 2021; 15:770011. [PMID: 34776857 PMCID: PMC8586522 DOI: 10.3389/fnins.2021.770011] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 09/30/2021] [Indexed: 12/03/2022] Open
Abstract
In the natural environment, organisms are constantly exposed to a continuous stream of sensory input. The dynamics of sensory input changes with organism's behaviour and environmental context. The contextual variations may induce >100-fold change in the parameters of the stimulation that an animal experiences. Thus, it is vital for the organism to adapt to the new diet of stimulation. The response properties of neurons, in turn, dynamically adjust to the prevailing properties of sensory stimulation, a process known as "neuronal adaptation." Neuronal adaptation is a ubiquitous phenomenon across all sensory modalities and occurs at different stages of processing from periphery to cortex. In spite of the wealth of research on contextual modulation and neuronal adaptation in visual and auditory systems, the neuronal and computational basis of sensory adaptation in somatosensory system is less understood. Here, we summarise the recent finding and views about the neuronal adaptation in the rodent whisker-mediated tactile system and further summarise the functional effect of neuronal adaptation on the response dynamics and encoding efficiency of neurons at single cell and population levels along the whisker-mediated touch system in rodents. Based on direct and indirect pieces of evidence presented here, we suggest sensory adaptation provides context-dependent functional mechanisms for noise reduction in sensory processing, salience processing and deviant stimulus detection, shift between integration and coincidence detection, band-pass frequency filtering, adjusting neuronal receptive fields, enhancing neural coding and improving discriminability around adapting stimuli, energy conservation, and disambiguating encoding of principal features of tactile stimuli.
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Affiliation(s)
- Mehdi Adibi
- Department of Physiology and Biomedicine Discovery Institute, Monash University, Clayton, VIC, Australia
- Department of Neuroscience and Padova Neuroscience Center (PNC), University of Padova, Padova, Italy
| | - Ilan Lampl
- Department of Brain Sciences, Weizmann Institute of Science, Rehovot, Israel
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12
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Humans Use a Temporally Local Code for Vibrotactile Perception. eNeuro 2021; 8:ENEURO.0263-21.2021. [PMID: 34625459 PMCID: PMC8570683 DOI: 10.1523/eneuro.0263-21.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Revised: 08/19/2021] [Accepted: 08/22/2021] [Indexed: 11/21/2022] Open
Abstract
Sensory environments are commonly characterized by specific physical features, which sensory systems might exploit using dedicated processing mechanisms. In the tactile sense, one such characteristic feature is frictional movement, which gives rise to short-lasting (<10 ms), information-carrying integument vibrations. Rather than generic integrative encoding (i.e., averaging or spectral analysis capturing the "intensity" and "best frequency"), the tactile system might benefit from, what we call a "temporally local" coding scheme that instantaneously detects and analyzes shapes of these short-lasting features. Here, by employing analytic psychophysical measurements, we tested whether the prerequisite of temporally local coding exists in the human tactile system. We employed pulsatile skin indentations at the fingertip that allowed us to trade manipulation of local pulse shape against changes in global intensity and frequency, achieved by adding pulses of the same shape. We found that manipulation of local pulse shape has strong effects on psychophysical performance, arguing for the notion that humans implement a temporally local coding scheme for perceptual decisions. As we found distinct differences in performance using different kinematic layouts of pulses, we inquired whether temporally local coding is tuned to a unique kinematic variable. This was not the case, since we observed different preferred kinematic variables in different ranges of pulse shapes. Using an established encoding model for primary afferences and indentation stimuli, we were able to demonstrate that the found kinematic preferences in human performance, may well be explained by the response characteristics of Pacinian corpuscles (PCs), a class of human tactile primary afferents.
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13
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Oladazimi M, Putelat T, Szalai R, Noda K, Shimoyama I, Champneys A, Schwarz C. Conveyance of texture signals along a rat whisker. Sci Rep 2021; 11:13570. [PMID: 34193889 PMCID: PMC8245408 DOI: 10.1038/s41598-021-92770-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 06/07/2021] [Indexed: 11/09/2022] Open
Abstract
Neuronal activities underlying a percept are constrained by the physics of sensory signals. In the tactile sense such constraints are frictional stick-slip events, occurring, amongst other vibrotactile features, when tactile sensors are in contact with objects. We reveal new biomechanical phenomena about the transmission of these microNewton forces at the tip of a rat's whisker, where they occur, to the base where they engage primary afferents. Using high resolution videography and accurate measurement of axial and normal forces at the follicle, we show that the conical and curved rat whisker acts as a sign-converting amplification filter for moment to robustly engage primary afferents. Furthermore, we present a model based on geometrically nonlinear Cosserat rod theory and a friction model that recreates the observed whole-beam whisker dynamics. The model quantifies the relation between kinematics (positions and velocities) and dynamic variables (forces and moments). Thus, only videographic assessment of acceleration is required to estimate forces and moments measured by the primary afferents. Our study highlights how sensory systems deal with complex physical constraints of perceptual targets and sensors.
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Affiliation(s)
- Maysam Oladazimi
- Systems Neurophysiology, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Otfried Müller Str. 25, 72076, Tübingen, Germany.,Systems Neurophysiology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
| | - Thibaut Putelat
- Department of Engineering Mathematics, University of Bristol, Bristol, BS8 1UB, UK.,Department of Sustainable Agriculture Sciences, Rothamsted Research, Harpenden, AL5 2JQ, UK
| | - Robert Szalai
- Department of Engineering Mathematics, University of Bristol, Bristol, BS8 1UB, UK
| | - Kentaro Noda
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, University of Tokyo, Tokyo, Japan.,Department of Intelligent Robotics, Toyama Prefectural University, Toyama, Japan
| | - Isao Shimoyama
- Department of Mechano-Informatics, Graduate School of Information Science and Technology, University of Tokyo, Tokyo, Japan.,Toyama Prefectural University, Toyama, Japan
| | - Alan Champneys
- Department of Engineering Mathematics, University of Bristol, Bristol, BS8 1UB, UK
| | - Cornelius Schwarz
- Systems Neurophysiology, Werner Reichardt Centre for Integrative Neuroscience, University of Tübingen, Otfried Müller Str. 25, 72076, Tübingen, Germany. .,Systems Neurophysiology, Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany.
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14
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Ramamurthy DL, Dodson HK, Krubitzer LA. Developmental plasticity of texture discrimination following early vision loss in the marsupial Monodelphis domestica. J Exp Biol 2021. [PMCID: PMC8181249 DOI: 10.1242/jeb.236646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
ABSTRACT
Behavioral strategies that depend on sensory information are not immutable; rather they can be shaped by the specific sensory context in which animals develop. This behavioral plasticity depends on the remarkable capacity of the brain to reorganize in response to alterations in the sensory environment, particularly when changes in sensory input occur at an early age. To study this phenomenon, we utilize the short-tailed opossum, a marsupial that has been a valuable animal model to study developmental plasticity due to the extremely immature state of its nervous system at birth. Previous studies in opossums have demonstrated that removal of retinal inputs early in development results in profound alterations to cortical connectivity and functional organization of visual and somatosensory cortex; however, behavioral consequences of this plasticity are not well understood. We trained early blind and sighted control opossums to perform a two-alternative forced choice texture discrimination task. Whisker trimming caused an acute deficit in discrimination accuracy for both groups, indicating the use of a primarily whisker-based strategy to guide choices based on tactile cues. Mystacial whiskers were important for performance in both groups; however, genal whiskers only contributed to behavioral performance in early blind animals. Early blind opossums significantly outperformed their sighted counterparts in discrimination accuracy, with discrimination thresholds that were lower by ∼75 μm. Our results support behavioral compensation following early blindness using tactile inputs, especially the whisker system.
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Affiliation(s)
- Deepa L. Ramamurthy
- Center for Neuroscience, University of California, Davis, Davis, CA 95618, USA
| | - Heather K. Dodson
- Center for Neuroscience, University of California, Davis, Davis, CA 95618, USA
| | - Leah A. Krubitzer
- Center for Neuroscience, University of California, Davis, Davis, CA 95618, USA
- Department of Psychology, University of California, Davis, Davis, CA 95618, USA
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15
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Su M, Liu J, Yu B, Zhou K, Sun C, Yang M, Zhao C. Loss of Calretinin in L5a impairs the formation of the barrel cortex leading to abnormal whisker-mediated behaviors. Mol Brain 2021; 14:67. [PMID: 33845857 PMCID: PMC8042711 DOI: 10.1186/s13041-021-00775-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 03/23/2021] [Indexed: 11/30/2022] Open
Abstract
The rodent whisker-barrel cortex system has been established as an ideal model for studying sensory information integration. The barrel cortex consists of barrel and septa columns that receive information input from the lemniscal and paralemniscal pathways, respectively. Layer 5a is involved in both barrel and septa circuits and play a key role in information integration. However, the role of layer 5a in the development of the barrel cortex remains unclear. Previously, we found that calretinin is dynamically expressed in layer 5a. In this study, we analyzed calretinin KO mice and found that the dendritic complexity and length of layer 5a pyramidal neurons were significantly decreased after calretinin ablation. The membrane excitability and excitatory synaptic transmission of layer 5a neurons were increased. Consequently, the organization of the barrels was impaired. Moreover, layer 4 spiny stellate cells were not able to properly gather, leading to abnormal formation of barrel walls as the ratio of barrel/septum size obviously decreased. Calretinin KO mice exhibited deficits in exploratory and whisker-associated tactile behaviors as well as social novelty preference. Our study expands our knowledge of layer 5a pyramidal neurons in the formation of barrel walls and deepens the understanding of the development of the whisker-barrel cortex system.
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Affiliation(s)
- Mingzhao Su
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing, 210009, China
| | - Junhua Liu
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing, 210009, China
| | - Baocong Yu
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing, 210009, China
| | - Kaixing Zhou
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing, 210009, China
| | - Congli Sun
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing, 210009, China
| | - Mengjie Yang
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing, 210009, China
| | - Chunjie Zhao
- Key Laboratory of Developmental Genes and Human Diseases, Ministry of Education, School of Medicine, Southeast University, Nanjing, 210009, China.
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16
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Gugig E, Sharma H, Azouz R. Gradient of tactile properties in the rat whisker pad. PLoS Biol 2020; 18:e3000699. [PMID: 33090990 PMCID: PMC7608947 DOI: 10.1371/journal.pbio.3000699] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 11/03/2020] [Accepted: 09/14/2020] [Indexed: 11/18/2022] Open
Abstract
The array of vibrissae on a rat's face is the first stage in a high-resolution tactile sensing system. Progressing from rostral to caudal in any vibrissae row results in an increase in whisker length and thickness. This may, in turn, provide a systematic map of separate tactile channels governed by the mechanical properties of the whiskers. To examine whether this map is expressed in a location-dependent transformation of tactile signals into whisker vibrations and neuronal responses, we monitored whiskers' movements across various surfaces and edges. We found a robust rostral-caudal (R-C) gradient of tactile information transmission in which rostral shorter vibrissae displayed a higher sensitivity and bigger differences in response to different textures, whereas longer caudal vibrissae were less sensitive. This gradient is evident in several dynamic properties of vibrissae trajectories. As rodents sample the environment with multiple vibrissae, we found that combining tactile signals from multiple vibrissae resulted in an increased sensitivity and bigger differences in response to the different textures. Nonetheless, we found that texture identity is not represented spatially across the whisker pad. Based on the responses of first-order sensory neurons, we found that they adhere to the tactile information conveyed by the vibrissae. That is, neurons innervating rostral vibrissae were better suited for texture discrimination, whereas neurons innervating caudal vibrissae were more suited for edge detection. These results suggest that the whisker array in rodents forms a sensory structure in which different facets of tactile information are transmitted through location-dependent gradient of vibrissae on the rat's face.
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Affiliation(s)
- Erez Gugig
- Department of Physiology and Cell Biology, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Hariom Sharma
- Department of Physiology and Cell Biology, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Rony Azouz
- Department of Physiology and Cell Biology, Zlotowski Center for Neuroscience, Ben-Gurion University of the Negev, Beer-Sheva, Israel
- * E-mail:
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17
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Harrell ER, Goldin MA, Bathellier B, Shulz DE. An elaborate sweep-stick code in rat barrel cortex. SCIENCE ADVANCES 2020; 6:6/38/eabb7189. [PMID: 32938665 PMCID: PMC7494352 DOI: 10.1126/sciadv.abb7189] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 07/23/2020] [Indexed: 06/11/2023]
Abstract
In rat barrel cortex, feature encoding schemes uncovered during broadband whisker stimulation are hard to reconcile with the simple stick-slip code observed during natural tactile behaviors, and this has hindered the development of a generalized computational framework. By designing broadband artificial stimuli to sample the inputs encoded under natural conditions, we resolve this disparity while markedly increasing the percentage of deep layer neurons found to encode whisker movements, as well as the diversity of these encoded features. Deep layer neurons encode two main types of events, sticks and sweeps, corresponding to high angular velocity bumps and large angular displacements with high velocity, respectively. Neurons can exclusively encode sticks or sweeps, or they can encode both, with or without direction selectivity. Beyond unifying coding theories from naturalistic and artificial stimulation studies, these findings delineate a simple and generalizable set of whisker movement features that can support a range of perceptual processes.
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Affiliation(s)
- Evan R Harrell
- Université Paris-Saclay, CNRS, Institut des neurosciences Paris-Saclay (NeuroPSI), Building 32/33, 1 avenue de la Terrasse, 91190, Gif-sur-Yvette, France.
| | - Matías A Goldin
- Université Paris-Saclay, CNRS, Institut des neurosciences Paris-Saclay (NeuroPSI), Building 32/33, 1 avenue de la Terrasse, 91190, Gif-sur-Yvette, France
| | - Brice Bathellier
- Université Paris-Saclay, CNRS, Institut des neurosciences Paris-Saclay (NeuroPSI), Building 32/33, 1 avenue de la Terrasse, 91190, Gif-sur-Yvette, France
| | - Daniel E Shulz
- Université Paris-Saclay, CNRS, Institut des neurosciences Paris-Saclay (NeuroPSI), Building 32/33, 1 avenue de la Terrasse, 91190, Gif-sur-Yvette, France.
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18
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Staiger JF, Petersen CCH. Neuronal Circuits in Barrel Cortex for Whisker Sensory Perception. Physiol Rev 2020; 101:353-415. [PMID: 32816652 DOI: 10.1152/physrev.00019.2019] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The array of whiskers on the snout provides rodents with tactile sensory information relating to the size, shape and texture of objects in their immediate environment. Rodents can use their whiskers to detect stimuli, distinguish textures, locate objects and navigate. Important aspects of whisker sensation are thought to result from neuronal computations in the whisker somatosensory cortex (wS1). Each whisker is individually represented in the somatotopic map of wS1 by an anatomical unit named a 'barrel' (hence also called barrel cortex). This allows precise investigation of sensory processing in the context of a well-defined map. Here, we first review the signaling pathways from the whiskers to wS1, and then discuss current understanding of the various types of excitatory and inhibitory neurons present within wS1. Different classes of cells can be defined according to anatomical, electrophysiological and molecular features. The synaptic connectivity of neurons within local wS1 microcircuits, as well as their long-range interactions and the impact of neuromodulators, are beginning to be understood. Recent technological progress has allowed cell-type-specific connectivity to be related to cell-type-specific activity during whisker-related behaviors. An important goal for future research is to obtain a causal and mechanistic understanding of how selected aspects of tactile sensory information are processed by specific types of neurons in the synaptically connected neuronal networks of wS1 and signaled to downstream brain areas, thus contributing to sensory-guided decision-making.
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Affiliation(s)
- Jochen F Staiger
- University Medical Center Göttingen, Institute for Neuroanatomy, Göttingen, Germany; and Laboratory of Sensory Processing, Faculty of Life Sciences, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Carl C H Petersen
- University Medical Center Göttingen, Institute for Neuroanatomy, Göttingen, Germany; and Laboratory of Sensory Processing, Faculty of Life Sciences, Brain Mind Institute, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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19
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Touch: Fluctuating Waves of Perception. Curr Biol 2020; 30:R934-R936. [PMID: 32810452 DOI: 10.1016/j.cub.2020.06.087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Does sensory input flow into the brain as a stream, or does it come in waves? New research shows that tactile information in the cortex rises and falls in phase with the forward and back motion of whiskers during surface exploration.
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20
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Isett BR, Feldman DE. Cortical Coding of Whisking Phase during Surface Whisking. Curr Biol 2020; 30:3065-3074.e5. [PMID: 32531284 DOI: 10.1016/j.cub.2020.05.064] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Revised: 04/16/2020] [Accepted: 05/19/2020] [Indexed: 12/27/2022]
Abstract
In rodent whisker sensation, whisker position signals, including whisking phase, are integrated with touch signals to enable spatially accurate tactile perception, but other functions of phase coding are unclear. We investigate how phase coding affects the neural coding of surface features during surface whisking. In mice performing rough-smooth discrimination, S1 units exhibit much stronger phase tuning during surface whisking than in prior studies of whisking in air. Among putative pyramidal cells, preferred phase tiles phase space, but protraction phases are strongly over-represented. Fast-spiking units are nearly all protraction tuned. This protraction bias increases the coding of stick-slip whisker events during protraction, suggesting that surface features are preferentially encoded during protraction. Correspondingly, protraction-tuned units encode rough-smooth texture better than retraction-tuned units and encode the precise spatial location of surface ridges with higher acuity. This suggests that protraction is the main information-gathering phase for high-resolution surface features, with phase coding organized to support this function.
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Affiliation(s)
- Brian R Isett
- Department of Molecular and Cellular Biology, and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Daniel E Feldman
- Department of Molecular and Cellular Biology, and Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
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21
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Vecchia D, Beltramo R, Vallone F, Chéreau R, Forli A, Molano-Mazón M, Bawa T, Binini N, Moretti C, Holtmaat A, Panzeri S, Fellin T. Temporal Sharpening of Sensory Responses by Layer V in the Mouse Primary Somatosensory Cortex. Curr Biol 2020; 30:1589-1599.e10. [PMID: 32169206 PMCID: PMC7198976 DOI: 10.1016/j.cub.2020.02.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 01/16/2020] [Accepted: 02/03/2020] [Indexed: 01/14/2023]
Abstract
The timing of stimulus-evoked spikes encodes information about sensory stimuli. Here we studied the neural circuits controlling this process in the mouse primary somatosensory cortex. We found that brief optogenetic activation of layer V pyramidal cells just after whisker deflection modulated the membrane potential of neurons and interrupted their long-latency whisker responses, increasing their accuracy in encoding whisker deflection time. In contrast, optogenetic inhibition of layer V during either passive whisker deflection or active whisking decreased accuracy in encoding stimulus or touch time, respectively. Suppression of layer V pyramidal cells increased reaction times in a texture discrimination task. Moreover, two-color optogenetic experiments revealed that cortical inhibition was efficiently recruited by layer V stimulation and that it mainly involved activation of parvalbumin-positive rather than somatostatin-positive interneurons. Layer V thus performs behaviorally relevant temporal sharpening of sensory responses through circuit-specific recruitment of cortical inhibition.
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Affiliation(s)
- Dania Vecchia
- Optical Approaches to Brain Function Laboratory, Istituto Italiano di Tecnologia, 16163 Genova, Italy; Neural Coding Laboratory, Istituto Italiano di Tecnologia, 16163 Genova and 38068 Rovereto, Italy
| | - Riccardo Beltramo
- Optical Approaches to Brain Function Laboratory, Istituto Italiano di Tecnologia, 16163 Genova, Italy
| | - Fabio Vallone
- Neural Coding Laboratory, Istituto Italiano di Tecnologia, 16163 Genova and 38068 Rovereto, Italy
| | - Ronan Chéreau
- Department of Basic Neurosciences, Geneva University Neurocenter, Faculty of Medicine, University of Geneva, 1206 Geneva, Switzerland
| | - Angelo Forli
- Optical Approaches to Brain Function Laboratory, Istituto Italiano di Tecnologia, 16163 Genova, Italy; Neural Coding Laboratory, Istituto Italiano di Tecnologia, 16163 Genova and 38068 Rovereto, Italy
| | - Manuel Molano-Mazón
- Neural Coding Laboratory, Istituto Italiano di Tecnologia, 16163 Genova and 38068 Rovereto, Italy; Neural Computation Laboratory, Center for Neuroscience and Cognitive Systems @UniTn, Istituto Italiano di Tecnologia, 38068 Rovereto, Italy
| | - Tanika Bawa
- Department of Basic Neurosciences, Geneva University Neurocenter, Faculty of Medicine, University of Geneva, 1206 Geneva, Switzerland
| | - Noemi Binini
- Optical Approaches to Brain Function Laboratory, Istituto Italiano di Tecnologia, 16163 Genova, Italy; Neural Coding Laboratory, Istituto Italiano di Tecnologia, 16163 Genova and 38068 Rovereto, Italy
| | - Claudio Moretti
- Optical Approaches to Brain Function Laboratory, Istituto Italiano di Tecnologia, 16163 Genova, Italy; Neural Coding Laboratory, Istituto Italiano di Tecnologia, 16163 Genova and 38068 Rovereto, Italy
| | - Anthony Holtmaat
- Department of Basic Neurosciences, Geneva University Neurocenter, Faculty of Medicine, University of Geneva, 1206 Geneva, Switzerland
| | - Stefano Panzeri
- Neural Coding Laboratory, Istituto Italiano di Tecnologia, 16163 Genova and 38068 Rovereto, Italy; Neural Computation Laboratory, Center for Neuroscience and Cognitive Systems @UniTn, Istituto Italiano di Tecnologia, 38068 Rovereto, Italy
| | - Tommaso Fellin
- Optical Approaches to Brain Function Laboratory, Istituto Italiano di Tecnologia, 16163 Genova, Italy; Neural Coding Laboratory, Istituto Italiano di Tecnologia, 16163 Genova and 38068 Rovereto, Italy.
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22
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Goshadrou F, Sadeghi B. Nucleus basalis of Meynert modulates signal processing in rat layer 5 somatosensory cortex but leads to memory impairment and tactile discrimination deficits following lesion. Behav Brain Res 2020; 386:112608. [DOI: 10.1016/j.bbr.2020.112608] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 02/27/2020] [Accepted: 03/12/2020] [Indexed: 11/25/2022]
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23
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Schyns PG, Zhan J, Jack RE, Ince RAA. Revealing the information contents of memory within the stimulus information representation framework. Philos Trans R Soc Lond B Biol Sci 2020; 375:20190705. [PMID: 32248774 PMCID: PMC7209912 DOI: 10.1098/rstb.2019.0705] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The information contents of memory are the cornerstone of the most influential models in cognition. To illustrate, consider that in predictive coding, a prediction implies that specific information is propagated down from memory through the visual hierarchy. Likewise, recognizing the input implies that sequentially accrued sensory evidence is successfully matched with memorized information (categorical knowledge). Although the existing models of prediction, memory, sensory representation and categorical decision are all implicitly cast within an information processing framework, it remains a challenge to precisely specify what this information is, and therefore where, when and how the architecture of the brain dynamically processes it to produce behaviour. Here, we review a framework that addresses these challenges for the studies of perception and categorization–stimulus information representation (SIR). We illustrate how SIR can reverse engineer the information contents of memory from behavioural and brain measures in the context of specific cognitive tasks that involve memory. We discuss two specific lessons from this approach that generally apply to memory studies: the importance of task, to constrain what the brain does, and of stimulus variations, to identify the specific information contents that are memorized, predicted, recalled and replayed. This article is part of the Theo Murphy meeting issue ‘Memory reactivation: replaying events past, present and future’.
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Affiliation(s)
- Philippe G Schyns
- Institute of Neuroscience and Psychology, University of Glasgow, Scotland G12 8QB, UK.,School of Psychology, University of Glasgow, Scotland G12 8QB, UK
| | - Jiayu Zhan
- Institute of Neuroscience and Psychology, University of Glasgow, Scotland G12 8QB, UK
| | - Rachael E Jack
- School of Psychology, University of Glasgow, Scotland G12 8QB, UK
| | - Robin A A Ince
- Institute of Neuroscience and Psychology, University of Glasgow, Scotland G12 8QB, UK
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24
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Gharaei S, Honnuraiah S, Arabzadeh E, Stuart GJ. Superior colliculus modulates cortical coding of somatosensory information. Nat Commun 2020; 11:1693. [PMID: 32245963 PMCID: PMC7125203 DOI: 10.1038/s41467-020-15443-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 03/02/2020] [Indexed: 12/05/2022] Open
Abstract
The cortex modulates activity in superior colliculus via a direct projection. What is largely unknown is whether (and if so how) the superior colliculus modulates activity in the cortex. Here, we investigate this issue and show that optogenetic activation of superior colliculus changes the input-output relationship of neurons in somatosensory cortex, enhancing responses to low amplitude whisker deflections. While there is no direct pathway from superior colliculus to somatosensory cortex, we found that activation of superior colliculus drives spiking in the posterior medial (POm) nucleus of the thalamus via a powerful monosynaptic pathway. Furthermore, POm neurons receiving input from superior colliculus provide monosynaptic excitatory input to somatosensory cortex. Silencing POm abolished the capacity of superior colliculus to modulate cortical whisker responses. Our findings indicate that the superior colliculus, which plays a key role in attention, modulates sensory processing in somatosensory cortex via a powerful di-synaptic pathway through the thalamus.
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Affiliation(s)
- Saba Gharaei
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia.
- Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University Node, Canberra, ACT, Australia.
| | - Suraj Honnuraiah
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
- Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University Node, Canberra, ACT, Australia
| | - Ehsan Arabzadeh
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia
- Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University Node, Canberra, ACT, Australia
| | - Greg J Stuart
- Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia.
- Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University Node, Canberra, ACT, Australia.
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25
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Shafiei F, Afarinesh MR, Golshan F, Haghpanah T, Sabzalizadeh M, Zangiabadi I, Sheibani V. Comparison of pre-pulse inhibition, tactile discrimination learning and barrel cortical neural response in adult male rats following chronic exposure to morphine, methadone and buprenorphine. Physiol Behav 2019; 212:112694. [PMID: 31622612 DOI: 10.1016/j.physbeh.2019.112694] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 09/14/2019] [Accepted: 09/27/2019] [Indexed: 12/01/2022]
Abstract
Chronic exposure to opioids is the most common treatment plan to reduce the pain. In this study, the stereotyped behaviors and cognitive functions related to different types of tactile and auditory inputs were investigated in the rats following chronic exposure to the morphine, methadone, and buprenorphine. Here, three addicted groups received morphine, methadone, and buprenorphine while the control rats received saline for 21 days. Our results demonstrated that the opioid-treated groups showed stereotyped behaviors including grooming and rearing. In the behavioral level, prepulse inhibition and preference indices were not changed significantly in the opioids-treated groups compared to those of the saline group as two criteria for acoustic startle reflex and tactile discrimination, respectively. In the neuronal level, chronic morphine and methadone treatment changed the response properties of the barrel cortical neurons to the whisker deflections in the experimental groups compared to the saline group. Thus, it was concluded that the excitatory receptive fields of neurons in the barrel cortex can be changed as a result of chronic exposure to morphine and methadone.
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Affiliation(s)
- Faezeh Shafiei
- Kerman Neuroscience Research Center, Institute of Neuropharmachology, Kerman University of Medical Sciences, Kerman, Iran; Kerman Cognitive Neuroscience Research Center, Institute of Neuropharmachology, Kerman University of Medical Sciences, Kerman, Iran
| | - Mohammad Reza Afarinesh
- Kerman Neuroscience Research Center, Institute of Neuropharmachology, Kerman University of Medical Sciences, Kerman, Iran; Kerman Cognitive Neuroscience Research Center, Institute of Neuropharmachology, Kerman University of Medical Sciences, Kerman, Iran.
| | - Fatemeh Golshan
- Kerman Neuroscience Research Center, Institute of Neuropharmachology, Kerman University of Medical Sciences, Kerman, Iran
| | - Tahereh Haghpanah
- Department of Anatomy, School of Afzalipour Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Mansoureh Sabzalizadeh
- Kerman Neuroscience Research Center, Institute of Neuropharmachology, Kerman University of Medical Sciences, Kerman, Iran
| | - Iman Zangiabadi
- Department of Anatomy, School of Afzalipour Medicine, Kerman University of Medical Sciences, Kerman, Iran
| | - Vahid Sheibani
- Kerman Neuroscience Research Center, Institute of Neuropharmachology, Kerman University of Medical Sciences, Kerman, Iran; Kerman Cognitive Neuroscience Research Center, Institute of Neuropharmachology, Kerman University of Medical Sciences, Kerman, Iran
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26
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Sistani S, Fatemi I, Shafeie SA, Kaeidi A, Azin M, Shamsizadeh A. The effect of Wi-Fi electromagnetic waves on neuronal response properties in rat barrel cortex. Somatosens Mot Res 2019; 36:292-297. [PMID: 31718372 DOI: 10.1080/08990220.2019.1689116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
There is a growing number of studies on the possible biological effects of Wi-Fi radiations on nervous system. In this study we investigated the effect of Wi-Fi exposure on single neuron responses to natural stimuli by using whisker to barrel pathway. This study was done on 29 male Wistar rats. Neuronal spontaneous activity and ON and OFF responses to displacement of principal whisker (PW), adjacent whisker (AW) and combination of PW-AW stimulation (as natural stimuli) were recorded in barrel cortex of anaesthetised rats. A D-link Wi-Fi device was used for 1 h exposure to 2.4 GHz microwaves in data mode (18.2 dBm and 44% for power and duty cycle). A condition test ratio (CTR) was calculated for assessing neuronal integrative properties. Wi-Fi radiations decreased CTR for ON responses. However, neuronal spontaneous activity and ON and OFF responses were not significantly changed following exposure to Wi-Fi signals. The results of this study demonstrated that exposure to Wi-Fi radiation could modulate integrative responses to natural stimuli in barrel cortex.
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Affiliation(s)
- Sahar Sistani
- Physiology-pharmacology Research Center, Research Institute of Basic Medical Sciences, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
| | - Iman Fatemi
- Research Center for Tropical and Infectious Diseases, Kerman University of Medical Sciences, Kerman, Iran
| | - Seyed Ali Shafeie
- Neuroscience Research Center, Qom University of Medical Sciences, Qom Iran
| | - Ayat Kaeidi
- Physiology-pharmacology Research Center, Research Institute of Basic Medical Sciences, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
| | - Mahdieh Azin
- Physiology-pharmacology Research Center, Research Institute of Basic Medical Sciences, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
| | - Ali Shamsizadeh
- Physiology-pharmacology Research Center, Research Institute of Basic Medical Sciences, Rafsanjan University of Medical Sciences, Rafsanjan, Iran
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27
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Gerdjikov TV, Bergner CG, Schwarz C. Global Tactile Coding in Rat Barrel Cortex in the Absence of Local Cues. Cereb Cortex 2019; 28:2015-2027. [PMID: 28498957 DOI: 10.1093/cercor/bhx108] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Indexed: 11/15/2022] Open
Abstract
Although whisker-related perception is based predominantly on local, near-instantaneous coding, global, intensive coding, which integrates the vibrotactile signal over time, has also been shown to play a role given appropriate behavioral conditions. Here, we study global coding in isolation by studying head-fixed rats that identified pulsatile stimuli differing in pulse frequency but not in pulse waveforms, thus abolishing perception based on local coding. We quantified time locking and spike counts as likely variables underpinning the 2 coding schemes. Both neurometric variables contained substantial stimulus information, carried even by spikes of single barrel cortex neurons. To elucidate which type of information is actually used by the rats, we systematically compared psychometric with neurometric sensitivity based on the 2 coding schemes. Neurometric performance was calculated by using a population-encoding model incorporating the properties of our recorded neuron sample. We found that sensitivity calculated from spike counts sampled over long periods (>1 s) matched the performance of rats better than the one carried by spikes time-locked to the stimulus. We conclude that spike counts are more relevant to tactile perception when instantaneous kinematic parameters are not available.
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Affiliation(s)
- Todor V Gerdjikov
- Werner Reichardt Center for Integrative Neuroscience, Systems Neuroscience, Eberhard Karls University, 72076 Tübingen, Germany.,Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, Eberhard Karls University, 72076 Tübingen, Germany.,Department of Neuroscience, Psychology and Behaviour, University of Leicester, Leicester LE1 9HN, UK
| | - Caroline G Bergner
- Werner Reichardt Center for Integrative Neuroscience, Systems Neuroscience, Eberhard Karls University, 72076 Tübingen, Germany.,Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, Eberhard Karls University, 72076 Tübingen, Germany
| | - Cornelius Schwarz
- Werner Reichardt Center for Integrative Neuroscience, Systems Neuroscience, Eberhard Karls University, 72076 Tübingen, Germany.,Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, Eberhard Karls University, 72076 Tübingen, Germany
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28
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Adibi M. Whisker-Mediated Touch System in Rodents: From Neuron to Behavior. Front Syst Neurosci 2019; 13:40. [PMID: 31496942 PMCID: PMC6712080 DOI: 10.3389/fnsys.2019.00040] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 08/02/2019] [Indexed: 01/02/2023] Open
Abstract
A key question in systems neuroscience is to identify how sensory stimuli are represented in neuronal activity, and how the activity of sensory neurons in turn is “read out” by downstream neurons and give rise to behavior. The choice of a proper model system to address these questions, is therefore a crucial step. Over the past decade, the increasingly powerful array of experimental approaches that has become available in non-primate models (e.g., optogenetics and two-photon imaging) has spurred a renewed interest for the use of rodent models in systems neuroscience research. Here, I introduce the rodent whisker-mediated touch system as a structurally well-established and well-organized model system which, despite its simplicity, gives rise to complex behaviors. This system serves as a behaviorally efficient model system; known as nocturnal animals, along with their olfaction, rodents rely on their whisker-mediated touch system to collect information about their surrounding environment. Moreover, this system represents a well-studied circuitry with a somatotopic organization. At every stage of processing, one can identify anatomical and functional topographic maps of whiskers; “barrelettes” in the brainstem nuclei, “barreloids” in the sensory thalamus, and “barrels” in the cortex. This article provides a brief review on the basic anatomy and function of the whisker system in rodents.
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Affiliation(s)
- Mehdi Adibi
- School of Psychology, University of New South Wales, Sydney, NSW, Australia.,Tactile Perception and Learning Lab, International School for Advanced Studies (SISSA), Trieste, Italy.,Padua Neuroscience Center, University of Padua, Padua, Italy
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29
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Laboy-Juárez KJ, Ahn S, Feldman DE. A normalized template matching method for improving spike detection in extracellular voltage recordings. Sci Rep 2019; 9:12087. [PMID: 31427615 PMCID: PMC6700190 DOI: 10.1038/s41598-019-48456-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 08/05/2019] [Indexed: 11/09/2022] Open
Abstract
Spike sorting is the process of detecting and clustering action potential waveforms of putative single neurons from extracellular voltage recordings. Typically, spike detection uses a fixed voltage threshold and shadow period, but this approach often misses spikes during high firing rate epochs or noisy conditions. We developed a simple, data-driven spike detection method using a scaled form of template matching, based on the sliding cosine similarity between the extracellular voltage signal and mean spike waveforms of candidate single units. Performance was tested in whisker somatosensory cortex (S1) of anesthetized mice in vivo. The method consistently detected whisker-evoked spikes that were missed by the standard fixed threshold. Detection was improved most for spikes evoked by strong stimuli (40–70% increase), improved less for weaker stimuli, and unchanged for spontaneous spiking. This represents improved detection during spatiotemporally dense spiking, and yielded sharper sensory tuning estimates. We also benchmarked performance using computationally generated voltage data. Template matching detected ~85–90% of spikes compared to ~70% for the standard fixed threshold method, and was more tolerant to high firing rates and simulated recording noise. Thus, a simple template matching approach substantially improves detection of single-unit spiking for cortical physiology.
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Affiliation(s)
- Keven J Laboy-Juárez
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA, 94720, USA. .,Department of Organismic and Evolutionary Biology and Center for Brain Science, Harvard University, Cambridge, Massachusetts, USA.
| | - Seoiyoung Ahn
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA, 94720, USA
| | - Daniel E Feldman
- Department of Molecular and Cell Biology and Helen Wills Neuroscience Institute, University of California Berkeley, Berkeley, CA, 94720, USA
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30
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Wang Y, Cao P, Mei L, Yin W, Mao Y, Niu C, Zhang Z, Tao W. Microglia in the Primary Somatosensory Barrel Cortex Mediate Trigeminal Neuropathic Pain. Neuroscience 2019; 414:299-310. [PMID: 31181369 DOI: 10.1016/j.neuroscience.2019.05.034] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 05/16/2019] [Accepted: 05/17/2019] [Indexed: 02/07/2023]
Abstract
Trigeminal neuropathic pain (TGN) is an attacking, abrupt, electric-shock headache involving abnormal cortical activity. The neural mechanism underlying TGN remains elusive. In this study, we explored the role of microglia in the primary somatosensory barrel cortex (S1BF), which is a critical region for TGN, of a mouse model of TGN that displayed significant pain-related behaviors. Using electrophysiological recordings, we found robust neuronal hyperactivity in glutamatergic neurons of S1BF (GluS1BF). Chemogenetic inhibition of GluS1BF neurons significantly relieved mechanical allodynia in TGN mice. In naïve mice, chemogenetic activation of GluS1BF neurons induced pain sensitization. In addition, we found that microglia in the S1BF (microgliaS1BF) were significantly activated, with density and morphology changes. Intraperitoneal administration of minocycline, a microglia inhibitor, attenuated pain sensitization, and decreased GluS1BF neuronal activity. Together, these findings demonstrate the putative importance of microglia as a key regulator in TGN through actions on GluS1BF neuronal adaptation.
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Affiliation(s)
- Yuping Wang
- Hefei National Laboratory for Physical Sciences at the Microscale, Key Laboratory of Brain Function and Disease, Department of Biophysics and Neurobiology, University of Science and Technology of China, Hefei 230027, PR China
| | - Peng Cao
- Hefei National Laboratory for Physical Sciences at the Microscale, Key Laboratory of Brain Function and Disease, Department of Biophysics and Neurobiology, University of Science and Technology of China, Hefei 230027, PR China
| | - Lisheng Mei
- Hefei National Laboratory for Physical Sciences at the Microscale, Key Laboratory of Brain Function and Disease, Department of Biophysics and Neurobiology, University of Science and Technology of China, Hefei 230027, PR China
| | - Weiwei Yin
- Hefei National Laboratory for Physical Sciences at the Microscale, Key Laboratory of Brain Function and Disease, Department of Biophysics and Neurobiology, University of Science and Technology of China, Hefei 230027, PR China
| | - Yu Mao
- Hefei National Laboratory for Physical Sciences at the Microscale, Key Laboratory of Brain Function and Disease, Department of Biophysics and Neurobiology, University of Science and Technology of China, Hefei 230027, PR China; Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei 230022, PR China
| | - Chaoshi Niu
- Department of Neurosurgery, The First Affiliated Hospital of University of Science and Technology of China, Hefei 230001, PR China
| | - Zhi Zhang
- Hefei National Laboratory for Physical Sciences at the Microscale, Key Laboratory of Brain Function and Disease, Department of Biophysics and Neurobiology, University of Science and Technology of China, Hefei 230027, PR China.
| | - Wenjuan Tao
- Hefei National Laboratory for Physical Sciences at the Microscale, Key Laboratory of Brain Function and Disease, Department of Biophysics and Neurobiology, University of Science and Technology of China, Hefei 230027, PR China; Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei 230022, PR China.
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31
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State-aware detection of sensory stimuli in the cortex of the awake mouse. PLoS Comput Biol 2019; 15:e1006716. [PMID: 31150385 PMCID: PMC6561583 DOI: 10.1371/journal.pcbi.1006716] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 06/12/2019] [Accepted: 05/15/2019] [Indexed: 11/19/2022] Open
Abstract
Cortical responses to sensory inputs vary across repeated presentations of identical stimuli, but how this trial-to-trial variability impacts detection of sensory inputs is not fully understood. Using multi-channel local field potential (LFP) recordings in primary somatosensory cortex (S1) of the awake mouse, we optimized a data-driven cortical state classifier to predict single-trial sensory-evoked responses, based on features of the spontaneous, ongoing LFP recorded across cortical layers. Our findings show that, by utilizing an ongoing prediction of the sensory response generated by this state classifier, an ideal observer improves overall detection accuracy and generates robust detection of sensory inputs across various states of ongoing cortical activity in the awake brain, which could have implications for variability in the performance of detection tasks across brain states. Establishing the link between neural activity and behavior is a central goal of neuroscience. One context in which to examine this link is in a sensory detection task, in which an animal is trained to report the presence of a barely perceptible sensory stimulus. In such tasks, both sensory responses in the brain and behavioral responses are highly variable. A simple hypothesis, originating in signal detection theory, is that perceived inputs generate neural activity that cross some threshold for detection. According to this hypothesis, sensory response variability would predict behavioral variability, but previous studies have not born out this prediction. Further complicating the picture, sensory response variability is partially dependent on the ongoing state of cortical activity, and we wondered whether this could resolve the mismatch between response variability and behavioral variability. Here, we use a computational approach to study an adaptive observer that utilizes an ongoing prediction of sensory responsiveness to detect sensory inputs. This observer has higher overall accuracy than the standard ideal observer. Moreover, because of the adaptation, the observer breaks the direct link between neural and behavioral variability, which could resolve discrepancies arising in past studies. We suggest new experiments to test our theory.
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Whisker Vibrations and the Activity of Trigeminal Primary Afferents in Response to Airflow. J Neurosci 2019; 39:5881-5896. [PMID: 31097620 DOI: 10.1523/jneurosci.2971-18.2019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 04/18/2019] [Accepted: 04/30/2019] [Indexed: 11/21/2022] Open
Abstract
Rodents are the most commonly studied model system in neuroscience, but surprisingly few studies investigate the natural sensory stimuli that rodent nervous systems evolved to interpret. Even fewer studies examine neural responses to these natural stimuli. Decades of research have investigated the rat vibrissal (whisker) system in the context of direct touch and tactile stimulation, but recent work has shown that rats also use their whiskers to help detect and localize airflow. The present study investigates the neural basis for this ability as dictated by the mechanical response of whiskers to airflow. Mechanical experiments show that a whisker's vibration magnitude depends on airspeed and the intrinsic shape of the whisker. Surprisingly, the direction of the whisker's vibration changes as a function of airflow speed: vibrations transition from parallel to perpendicular with respect to the airflow as airspeed increases. Recordings from primary sensory trigeminal ganglion neurons show that these neurons exhibit responses consistent with those that would be predicted from direct touch. Trigeminal neuron firing rate increases with airspeed, is modulated by the orientation of the whisker relative to the airflow, and is influenced by the whisker's resonant frequencies. We develop a simple model to describe how a population of neurons could leverage mechanical relationships to decode both airspeed and direction. These results open new avenues for studying vibrissotactile regions of the brain in the context of evolutionarily important airflow-sensing behaviors and olfactory search. Although this study used only female rats, all results are expected to generalize to male rats.SIGNIFICANCE STATEMENT The rodent vibrissal (whisker) system has been studied for decades in the context of direct tactile sensation, but recent work has indicated that rats also use whiskers to help localize airflow. Neural circuits in somatosensory regions of the rodent brain thus likely evolved in part to process airflow information. This study investigates the whiskers' mechanical response to airflow and the associated neural response. Airspeed affects the magnitude of whisker vibration and the response magnitude of whisker-sensitive primary sensory neurons in the trigeminal ganglion. Surprisingly, the direction of vibration and the associated directionally dependent neural response changes with airspeed. These findings suggest a population code for airflow speed and direction and open new avenues for studying vibrissotactile regions of the brain.
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33
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Maravall M. Sensory Decision-Making: Rats Sleuth Evidence through Active Sensing. Curr Biol 2019; 29:R317-R319. [DOI: 10.1016/j.cub.2019.03.034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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34
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Zuo Y, Diamond ME. Rats Generate Vibrissal Sensory Evidence until Boundary Crossing Triggers a Decision. Curr Biol 2019; 29:1415-1424.e5. [PMID: 31006570 DOI: 10.1016/j.cub.2019.03.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 11/19/2018] [Accepted: 03/13/2019] [Indexed: 11/24/2022]
Abstract
Behaviors in which primates collect externally generated streams of sensory evidence, such as judgment of random dot motion direction, are explained by a bounded integration decision model. Does this model extend to rodents, and does it account for behavior in which the motor system generates evidence through interactions with the environment? In this study, rats palpated surfaces to identify the texture before them, showing marked trial-to-trial variability in the number of touches prior to expressing their choice. By high-speed video, we tracked whisker kinematic features and characterized how they encoded the contacted texture. Next, we quantified the evidence for each candidate texture transmitted on each touch by the specified whisker kinematic features. The instant of choice was well fit by modeling the brain as an integrator that gives the greatest weight to vibrissal evidence on first touch and exponentially less weight to evidence on successive touches; according to this model, the rat makes a decision when the accumulated quantity of evidence for one texture reaches a boundary. In summary, evidence appears to be accumulated within the brain until sufficient to support a well-grounded choice. These findings extend the framework of bounded sensory integration from primates to rodents and from passively received evidence to evidence that is actively generated by the sensorimotor system.
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Affiliation(s)
- Yanfang Zuo
- Tactile Perception and Learning Lab, International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste, Italy
| | - Mathew E Diamond
- Tactile Perception and Learning Lab, International School for Advanced Studies (SISSA), Via Bonomea 265, 34136 Trieste, Italy.
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35
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Ranjbar-Slamloo Y, Arabzadeh E. Diverse tuning underlies sparse activity in layer 2/3 vibrissal cortex of awake mice. J Physiol 2019; 597:2803-2817. [PMID: 30932197 DOI: 10.1113/jp277506] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 03/22/2019] [Indexed: 12/23/2022] Open
Abstract
KEY POINTS Sparse population activity is a common feature observed across cortical areas, yet the implications for sensory coding are not clear. We recorded single neuron activity in the vibrissal somatosensory cortex of awake head-fixed mice using the cell-attached technique. Unlike the anaesthetised condition, in awake mice a high-velocity, piezo-controlled whisker deflection excited only a small fraction of neurons. Manual probing of whiskers revealed that the majority of these silent neurons could be activated by specific forms of whisker-object contact. Our results suggest that sparse coding in vibrissal cortex may be due to high dimensionality of the stimulus space and narrow tuning of individual neurons. ABSTRACT It is widely reported that superficial layers of the somatosensory cortex exhibit sparse firing. This sparseness could reflect weak feedforward sensory inputs that are not sufficient to generate action potentials in these layers. Alternatively, sparseness might reflect tuning to unknown or higher-level complex features that are not fully explored in the stimulus space. Here, we examined these hypotheses by applying a range of vibrotactile and manual vibrissal stimuli in awake, head-fixed mice while performing loose-seal cell-attached recordings from the vibrissal primary somatosensory (vS1) cortex. A high-velocity stimulus delivered by a piezo-electric actuator evoked activity in a small fraction of regular spiking supragranular neurons (23%) in the awake condition. However, a majority of the supragranular regular spiking neurons (84%) were driven by manual stimulation of whiskers. Our results suggest that most neurons in the superficial layers of vS1 cortex contribute to coding in the awake condition when neurons may encounter their preferred feature(s) during whisker-object interactions.
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Affiliation(s)
- Yadollah Ranjbar-Slamloo
- Eccles Institute of Neuroscience, The John Curtin School of Medical Research, The Australian National University, Canberra, Australian Capital Territory, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University Node, Canberra, Australian Capital Territory, Australia
| | - Ehsan Arabzadeh
- Eccles Institute of Neuroscience, The John Curtin School of Medical Research, The Australian National University, Canberra, Australian Capital Territory, Australia.,Australian Research Council Centre of Excellence for Integrative Brain Function, The Australian National University Node, Canberra, Australian Capital Territory, Australia
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36
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Prediction of Choice from Competing Mechanosensory and Choice-Memory Cues during Active Tactile Decision Making. J Neurosci 2019; 39:3921-3933. [PMID: 30850514 PMCID: PMC6520515 DOI: 10.1523/jneurosci.2217-18.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2018] [Revised: 01/11/2019] [Accepted: 01/16/2019] [Indexed: 01/15/2023] Open
Abstract
Perceptual decision making is an active process where animals move their sense organs to extract task-relevant information. To investigate how the brain translates sensory input into decisions during active sensation, we developed a mouse active touch task where the mechanosensory input can be precisely measured and that challenges animals to use multiple mechanosensory cues. Male mice were trained to localize a pole using a single whisker and to report their decision by selecting one of three choices. Using high-speed imaging and machine vision, we estimated whisker-object mechanical forces at millisecond resolution. Mice solved the task by a sensory-motor strategy where both the strength and direction of whisker bending were informative cues to pole location. We found competing influences of immediate sensory input and choice memory on mouse choice. On correct trials, choice could be predicted from the direction and strength of whisker bending, but not from previous choice. In contrast, on error trials, choice could be predicted from previous choice but not from whisker bending. This study shows that animal choices during active tactile decision making can be predicted from mechanosensory and choice-memory signals, and provides a new task well suited for the future study of the neural basis of active perceptual decisions.SIGNIFICANCE STATEMENT Due to the difficulty of measuring the sensory input to moving sense organs, active perceptual decision making remains poorly understood. The whisker system provides a way forward since it is now possible to measure the mechanical forces due to whisker-object contact during behavior. Here we train mice in a novel behavioral task that challenges them to use rich mechanosensory cues but can be performed using one whisker and enables task-relevant mechanical forces to be precisely estimated. This approach enables rigorous study of how sensory cues translate into action during active, perceptual decision making. Our findings provide new insight into active touch and how sensory/internal signals interact to determine behavioral choices.
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37
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Tran CHT, Peringod G, Gordon GR. Astrocytes Integrate Behavioral State and Vascular Signals during Functional Hyperemia. Neuron 2018; 100:1133-1148.e3. [PMID: 30482689 DOI: 10.1016/j.neuron.2018.09.045] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Revised: 06/25/2018] [Accepted: 09/24/2018] [Indexed: 01/17/2023]
Abstract
Dynamic changes in astrocyte free Ca2+ regulate synaptic signaling and local blood flow. Although astrocytes are poised to integrate signals from synapses and the vasculature to perform their functional roles, it remains unclear what dictates astrocyte responses during neurovascular coupling under realistic conditions. We examined peri-arteriole and peri-capillary astrocytes in the barrel cortex of active mice in response to sensory stimulation or volitional behaviors. We observed an AMPA and NMDA receptor-dependent elevation in astrocyte endfoot Ca2+ that followed functional hyperemia onset. This delayed astrocyte Ca2+ signal was dependent on the animal's action at the time of measurement as well as a neurovascular pathway that linked to endothelial-derived nitric oxide. A similar elevation in endfoot Ca2+ was evoked using vascular chemogenetics or optogenetics, and opto-stimulated dilation recruited the same nitric oxide pathway as functional hyperemia. These data show that behavioral state and microvasculature influence astrocyte Ca2+ in active mice. VIDEO ABSTRACT.
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Affiliation(s)
- Cam Ha T Tran
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Govind Peringod
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Grant R Gordon
- Hotchkiss Brain Institute, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada.
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38
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Rey HG, De Falco E, Ison MJ, Valentin A, Alarcon G, Selway R, Richardson MP, Quian Quiroga R. Encoding of long-term associations through neural unitization in the human medial temporal lobe. Nat Commun 2018; 9:4372. [PMID: 30348996 PMCID: PMC6197188 DOI: 10.1038/s41467-018-06870-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 09/29/2018] [Indexed: 12/25/2022] Open
Abstract
Besides decades of research showing the role of the medial temporal lobe (MTL) in memory and the encoding of associations, the neural substrates underlying these functions remain unknown. We identified single neurons in the human MTL that responded to multiple and, in most cases, associated stimuli. We observed that most of these neurons exhibit no differences in their spike and local field potential (LFP) activity associated with the individual response-eliciting stimuli. In addition, LFP responses in the theta band preceded single neuron responses by ~70 ms, with the single trial phase providing fine tuning of the spike response onset. We postulate that the finding of similar neuronal responses to associated items provides a simple and flexible way of encoding memories in the human MTL, increasing the effective capacity for memory storage and successful retrieval. In this work, the authors recorded single neurons and field potentials from the human medial temporal lobe (MTL) and show indistinguishable responses to associated stimuli. This coding mechanism provides a simple and flexible way of encoding memories in the human MTL.
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Affiliation(s)
- Hernan G Rey
- Centre for Systems Neuroscience, University of Leicester, Leicester, LE1 7RH, UK
| | - Emanuela De Falco
- Centre for Systems Neuroscience, University of Leicester, Leicester, LE1 7RH, UK
| | - Matias J Ison
- Centre for Systems Neuroscience, University of Leicester, Leicester, LE1 7RH, UK.,School of Psychology, University of Nottingham, Nottingham, NG7 2RD, UK
| | - Antonio Valentin
- Division of Neuroscience, Institute of Psychiatry Psychology and Neuroscience, King's College London, London, SE5 8AF, UK.,Department of Clinical Neurophysiology, King's College Hospital NHS Trust, London, SE5 9RS, UK
| | - Gonzalo Alarcon
- Division of Neuroscience, Institute of Psychiatry Psychology and Neuroscience, King's College London, London, SE5 8AF, UK.,Department of Clinical Neurophysiology, King's College Hospital NHS Trust, London, SE5 9RS, UK.,Comprehensive Epilepsy Center, Neuroscience Institute, Academic Health Systems, Hamad Medical Corporation, Doha, PO Box 3050, Qatar
| | - Richard Selway
- Department of Neurosurgery, King's College Hospital NHS Trust, London, SE5 9RS, UK
| | - Mark P Richardson
- Division of Neuroscience, Institute of Psychiatry Psychology and Neuroscience, King's College London, London, SE5 8AF, UK
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Goldin MA, Harrell ER, Estebanez L, Shulz DE. Rich spatio-temporal stimulus dynamics unveil sensory specialization in cortical area S2. Nat Commun 2018; 9:4053. [PMID: 30282992 PMCID: PMC6170455 DOI: 10.1038/s41467-018-06585-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 09/12/2018] [Indexed: 11/21/2022] Open
Abstract
Tactile perception in rodents depends on simultaneous, multi-whisker contacts with objects. Although it is known that neurons in secondary somatosensory cortex (wS2) respond to individual deflections of many whiskers, wS2′s precise function remains unknown. The convergence of information from multiple whiskers into wS2 neurons suggests that they are good candidates for integrating multi-whisker information. Here, we apply stimulation patterns with rich dynamics simultaneously to 24 macro-vibrissae of rats while recording large populations of single neurons. Varying inter-whisker correlations without changing single whisker statistics, we observe pronounced supra-linear multi-whisker integration. Using novel analysis methods, we show that continuous multi-whisker movements contribute to the firing of wS2 neurons over long temporal windows, facilitating spatio-temporal integration. In contrast, primary cortex (wS1) neurons encode fine features of whisker movements on precise temporal scales. These results provide the first description of wS2′s representation during multi-whisker stimulation and outline its specialized role in parallel to wS1 tactile processing. Sensory tuning properties of neurons in the secondary whisker somatosensory cortex (wS2) are not well understood. Here, the authors report that wS2 neurons supralinearly integrate concurrent multi-whisker input with larger temporal windows than primary somatosensory cortex.
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Affiliation(s)
- Matías A Goldin
- Unité de Neurosciences, Information et Complexité, UNIC-FRE3693, Centre National de la Recherche Scientifique, Gif sur Yvette, 91198, France
| | - Evan R Harrell
- Unité de Neurosciences, Information et Complexité, UNIC-FRE3693, Centre National de la Recherche Scientifique, Gif sur Yvette, 91198, France
| | - Luc Estebanez
- Unité de Neurosciences, Information et Complexité, UNIC-FRE3693, Centre National de la Recherche Scientifique, Gif sur Yvette, 91198, France
| | - Daniel E Shulz
- Unité de Neurosciences, Information et Complexité, UNIC-FRE3693, Centre National de la Recherche Scientifique, Gif sur Yvette, 91198, France.
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Oladazimi M, Brendel W, Schwarz C. Biomechanical Texture Coding in Rat Whiskers. Sci Rep 2018; 8:11139. [PMID: 30042423 PMCID: PMC6057990 DOI: 10.1038/s41598-018-29225-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 07/09/2018] [Indexed: 11/30/2022] Open
Abstract
Classically, texture discrimination has been thought to be based on ‘global’ codes, i.e. frequency (signal analysis based on Fourier analysis) or intensity (signal analysis based on averaging), which both rely on integration of the vibrotactile signal across time and/or space. Recently, a novel ‘local’ coding scheme based on the waveform of frictional movements, discrete short lasting kinematic events (i.e. stick-slip movements called slips) has been formulated. We performed biomechanical measurements of relative movements of a rat vibrissa across sandpapers of different roughness. We find that the classic global codes convey some information about texture identity, but are consistently outperformed by the slip-based local code. Moreover, the slip code also surpasses the global ones in coding for active scanning parameters. This is remarkable as it suggests that the slip code would explicitly allow the whisking rat to optimize perception by selecting goal-specific scanning strategies.
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Affiliation(s)
- Maysam Oladazimi
- Systems Neurophysiology, Werner Reichardt Centre for Integrative Neuroscience, Eberhard Karls University of Tübingen, Tübingen, Germany.,Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Wieland Brendel
- Computational Neuroscience, Werner Reichardt Centre for Integrative Neuroscience, Eberhard Karls University of Tübingen, Tübingen, Germany
| | - Cornelius Schwarz
- Systems Neurophysiology, Werner Reichardt Centre for Integrative Neuroscience, Eberhard Karls University of Tübingen, Tübingen, Germany. .,Department of Cognitive Neurology, Hertie Institute for Clinical Brain Research, Eberhard Karls University of Tübingen, Tübingen, Germany.
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41
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Devilbiss DM. Consequences of tuning network function by tonic and phasic locus coeruleus output and stress: Regulating detection and discrimination of peripheral stimuli. Brain Res 2018; 1709:16-27. [PMID: 29908165 DOI: 10.1016/j.brainres.2018.06.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 05/23/2018] [Accepted: 06/12/2018] [Indexed: 12/15/2022]
Abstract
Flexible and adaptive behaviors have evolved with increasing complexity and numbers of neuromodulator systems. The neuromodulatory locus coeruleus-norepinephrine (LC-NE) system is central to regulating cognitive function in a behaviorally-relevant and arousal-dependent manner. Through its nearly ubiquitous efferent projections, the LC-NE system acts to modulate neuron function on a cell-by-cell basis and exert a spectrum of actions across different brain regions to optimize target circuit function. As LC neuron activity, NE signaling, and arousal level increases, cognitive performance improves over an inverted-U shaped curve. Additionally, LC neurons burst phasically in relation to novel or salient sensory stimuli and top-down decision- or response-related processes. Together, the variety of LC activity patterns and complex actions of the LC-NE system indicate that the LC-NE system may dynamically regulate the function of target neural circuits. The manner in which neural networks encode, represent, and perform neurocomputations continue to be revealed. This has improved our ability to understand the optimization of neural circuits by NE and generation of flexible and adaptive goal-directed behaviors. In this review, the rat vibrissa somatosensory system is explored as a model neural circuit to bridge known modulatory actions of NE and changes in cognitive function. It is argued that fluid transitions between neural computational states reflect the ability of this sensory system to shift between two principal functions: detection of novel or salient sensory information and detailed descriptions of sensory information. Such flexibility in circuit function is likely critical for producing context-appropriate sensory signal processing. Nonetheless, many challenges remain including providing a causal link between NE mediated changes in sensory neural coding and perceptual changes, as well as extending these principles to higher cognitive functions including behavioral flexibility and decision making.
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Affiliation(s)
- David M Devilbiss
- Department of Cell Biology and Neuroscience, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084, United States.
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42
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Martini FJ, Molano-Mazón M, Maravall M. Interspersed Distribution of Selectivity to Kinematic Stimulus Features in Supragranular Layers of Mouse Barrel Cortex. Cereb Cortex 2018; 27:3782-3789. [PMID: 28334121 DOI: 10.1093/cercor/bhx019] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 12/14/2016] [Indexed: 01/17/2023] Open
Abstract
Neurons in the primary sensory regions of neocortex have heterogeneous response properties. The spatial arrangement of neurons with particular response properties is a key aspect of population representations and can shed light on how local circuits are wired. Here, we investigated how neurons with sensitivity to different kinematic features of whisker stimuli are distributed across local circuits in supragranular layers of the barrel cortex. Using 2-photon calcium population imaging in anesthetized mice, we found that nearby neurons represent diverse kinematic features, providing a rich population representation at the local scale. Neurons interspersed in space therefore responded differently to a common stimulus kinematic feature. Conversely, neurons with similar feature selectivity were located no closer to each other than predicted by a random distribution null hypothesis. This finding relied on defining a null hypothesis that was specific for testing the spatial distribution of tuning across neurons. We also measured how neurons sensitive to specific features were distributed relative to barrel boundaries, and found no systematic organization. Our results are compatible with randomly distributed selectivity to kinematic features, with no systematic ordering superimposed upon the whisker map.
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Affiliation(s)
- Francisco J Martini
- Instituto de Neurociencias de Alicante UMH-CSIC, Avda. Ramón y Cajal s/n, Campus de San Juan, 03550 Sant Joan d'Alacant, Spain
| | - Manuel Molano-Mazón
- Instituto de Neurociencias de Alicante UMH-CSIC, Avda. Ramón y Cajal s/n, Campus de San Juan, 03550 Sant Joan d'Alacant, Spain.,Laboratory of Neural Computation, Center for Neuroscience and Cognitive Systems @UniTn, Istituto Italiano di Tecnologia, 38068 Rovereto, Italy
| | - Miguel Maravall
- Instituto de Neurociencias de Alicante UMH-CSIC, Avda. Ramón y Cajal s/n, Campus de San Juan, 03550 Sant Joan d'Alacant, Spain.,Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton, UK
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43
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Vaxenburg R, Wyche I, Svoboda K, Efros AL, Hires SA. Dynamic cues for whisker-based object localization: An analytical solution to vibration during active whisker touch. PLoS Comput Biol 2018; 14:e1006032. [PMID: 29584719 PMCID: PMC5889188 DOI: 10.1371/journal.pcbi.1006032] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 04/06/2018] [Accepted: 02/08/2018] [Indexed: 11/24/2022] Open
Abstract
Vibrations are important cues for tactile perception across species. Whisker-based sensation in mice is a powerful model system for investigating mechanisms of tactile perception. However, the role vibration plays in whisker-based sensation remains unsettled, in part due to difficulties in modeling the vibration of whiskers. Here, we develop an analytical approach to calculate the vibrations of whiskers striking objects. We use this approach to quantify vibration forces during active whisker touch at a range of locations along the whisker. The frequency and amplitude of vibrations evoked by contact are strongly dependent on the position of contact along the whisker. The magnitude of vibrational shear force and bending moment is comparable to quasi-static forces. The fundamental vibration frequencies are in a detectable range for mechanoreceptor properties and below the maximum spike rates of primary sensory afferents. These results suggest two dynamic cues exist that rodents can use for object localization: vibration frequency and comparison of vibrational to quasi-static force magnitude. These complement the use of quasi-static force angle as a distance cue, particularly for touches close to the follicle, where whiskers are stiff and force angles hardly change during touch. Our approach also provides a general solution to calculation of whisker vibrations in other sensing tasks. Vibrations play an important role in the sense of touch in many species, but exactly how they influence touch perception remains mysterious. An important reason for this mystery is the difficulty in measuring vibrations during touch. Mice are a powerful model system for investigating touch perception because they actively sweep their whiskers into objects and the resulting bending from touch can be video recorded. However, vibrations of the whiskers during touch are usually too small and fast to be seen. To overcome this limitation, we develop a new mathematical approach to calculating whisker vibrations from the speed at impact, maximum whisker bending during touch, and location of contact along a whisker, which is more easily observed. We find that vibration frequency and amplitude is strongly dependent on the location of contact along the whisker, which mice may use to deduce the distance between their face and touched objects. We confirm our calculations with high-speed imaging of whisker vibration during touch.
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Affiliation(s)
- Roman Vaxenburg
- Computational Materials Science Center, George Mason University, Fairfax, Virginia, United States of America
| | - Isis Wyche
- Section of Neurobiology, Department of Biological Sciences, University of South California, Los Angeles, California, United States of America
| | - Karel Svoboda
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, Virginia, United States of America
| | - Alexander L. Efros
- Center for Computational Material Science, Code 6390, Naval Research Laboratory, Washington, DC, United States of America
| | - Samuel Andrew Hires
- Section of Neurobiology, Department of Biological Sciences, University of South California, Los Angeles, California, United States of America
- * E-mail:
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Perez-Rando M, Castillo-Gomez E, Bueno-Fernandez C, Nacher J. The TrkB agonist 7,8-dihydroxyflavone changes the structural dynamics of neocortical pyramidal neurons and improves object recognition in mice. Brain Struct Funct 2018; 223:2393-2408. [PMID: 29500536 DOI: 10.1007/s00429-018-1637-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 02/20/2018] [Indexed: 01/17/2023]
Abstract
BDNF and its receptor TrkB have important roles in neurodevelopment, neural plasticity, learning, and memory. Alterations in TrkB expression have been described in different CNS disorders. Therefore, drugs interacting with TrkB, specially agonists, are promising therapeutic tools. Among them, the recently described 7,8-dihydroxyflavone (DHF), an orally bioactive compound, has been successfully tested in animal models of these diseases. Recent studies have shown the influence of this drug on the structure of pyramidal neurons, specifically on dendritic spine density. However, there is no information yet on how DHF may alter the structural dynamics of these neurons (i.e., real-time study of the addition/elimination of dendritic spines and axonal boutons). To gain knowledge on these effects of DHF, we have performed a real-time analysis of spine and axonal dynamics in pyramidal neurons of barrel cortex, using cranial windows and 2-photon microscopy during a chronic oral treatment with this drug. After confirming TrkB expression in these neurons, we found that DHF increased the gain rates of spines and axonal boutons, as well as improved object recognition memory. These results help to understand how the activation of the BDNF-TrkB system can improve basic behavioral tasks through changes in the structural dynamics of pyramidal neurons. Moreover, they highlight DHF as a promising therapeutic vector for certain brain disorders in which this system is altered.
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Affiliation(s)
- Marta Perez-Rando
- Neurobiology Unit, Cell Biology Department, Program in Neurosciences and Interdisciplinary Research Structure for Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Dr. Moliner, 50, Burjassot, 46100, Spain
| | - Esther Castillo-Gomez
- Neurobiology Unit, Cell Biology Department, Program in Neurosciences and Interdisciplinary Research Structure for Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Dr. Moliner, 50, Burjassot, 46100, Spain. .,CIBERSAM: Spanish National Network for Research in Mental Health, Valencia, Spain. .,Department of Medicine, School of Medical Sciences, Universitat Jaume I, Vicente Sos Banyat s/n, 12071, Castellón de la Plana, Spain.
| | - Clara Bueno-Fernandez
- Neurobiology Unit, Cell Biology Department, Program in Neurosciences and Interdisciplinary Research Structure for Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Dr. Moliner, 50, Burjassot, 46100, Spain
| | - Juan Nacher
- Neurobiology Unit, Cell Biology Department, Program in Neurosciences and Interdisciplinary Research Structure for Biotechnology and Biomedicine (BIOTECMED), Universitat de València, Dr. Moliner, 50, Burjassot, 46100, Spain. .,CIBERSAM: Spanish National Network for Research in Mental Health, Valencia, Spain. .,Fundación Investigación Hospital Clínico de Valencia, INCLIVA, Valencia, Spain.
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45
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Isett BR, Feasel SH, Lane MA, Feldman DE. Slip-Based Coding of Local Shape and Texture in Mouse S1. Neuron 2018; 97:418-433.e5. [PMID: 29307709 PMCID: PMC5773356 DOI: 10.1016/j.neuron.2017.12.021] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 10/23/2017] [Accepted: 12/14/2017] [Indexed: 01/13/2023]
Abstract
Tactile objects have both local geometry (shape) and broader macroscopic texture, but how these different spatial scales are simultaneously encoded during active touch is unknown. In the whisker system, we tested for a shared code based on localized whisker micromotions (stick-slips) and slip-evoked spikes. We trained mice to discriminate smooth from rough surfaces, including ridged gratings and sandpaper. Whisker slips locked to ridges and evoked temporally precise spikes (<10 ms jitter) in somatosensory cortex (S1) that could resolve ridges with ∼1 mm accuracy. Slip-sensitive neurons also encoded touch and texture. On rough surfaces, both slip-evoked spikes and an additional non-slip signal elevated mean firing rate, allowing accurate rough-smooth texture decoding from population firing rate. Eighteen percent of neurons were selective among rough surfaces. Thus, slips elicit spatially and temporally precise spiking in S1 that simultaneously encodes local shape (ridges) and is integrated into a macroscopic firing rate code for roughness.
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Affiliation(s)
- Brian R Isett
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Sierra H Feasel
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Monet A Lane
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Daniel E Feldman
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720, USA.
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46
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Information Processing Across Behavioral States: Modes of Operation and Population Dynamics in Rodent Sensory Cortex. Neuroscience 2018; 368:214-228. [DOI: 10.1016/j.neuroscience.2017.09.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Revised: 09/08/2017] [Accepted: 09/10/2017] [Indexed: 11/24/2022]
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47
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Liu Y, He K, Chen G, Leow WR, Chen X. Nature-Inspired Structural Materials for Flexible Electronic Devices. Chem Rev 2017; 117:12893-12941. [DOI: 10.1021/acs.chemrev.7b00291] [Citation(s) in RCA: 448] [Impact Index Per Article: 64.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Yaqing Liu
- Innovative Centre for Flexible
Devices (iFLEX), School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Ke He
- Innovative Centre for Flexible
Devices (iFLEX), School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Geng Chen
- Innovative Centre for Flexible
Devices (iFLEX), School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Wan Ru Leow
- Innovative Centre for Flexible
Devices (iFLEX), School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Xiaodong Chen
- Innovative Centre for Flexible
Devices (iFLEX), School of Materials Science and Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
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48
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Helmchen F, Gilad A, Chen JL. Neocortical dynamics during whisker-based sensory discrimination in head-restrained mice. Neuroscience 2017; 368:57-69. [PMID: 28919043 DOI: 10.1016/j.neuroscience.2017.09.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 08/30/2017] [Accepted: 09/01/2017] [Indexed: 10/18/2022]
Abstract
A fundamental task frequently encountered by brains is to rapidly and reliably discriminate between sensory stimuli of the same modality, be it distinct auditory sounds, odors, visual patterns, or tactile textures. A key mammalian brain structure involved in discrimination behavior is the neocortex. Sensory processing not only involves the respective primary sensory area, which is crucial for perceptual detection, but additionally relies on cortico-cortical communication among several regions including higher-order sensory areas as well as frontal cortical areas. It remains elusive how these regions exchange information to process neural representations of distinct stimuli to bring about a decision and initiate appropriate behavioral responses. Likewise, it is poorly understood how these neural computations are conjured during task learning. In this review, we discuss recent studies investigating cortical dynamics during discrimination behaviors that utilize head-fixed behavioral tasks in combination with in vivo electrophysiology, two-photon calcium imaging, and cell-type-specific targeting. We particularly focus on information flow in distinct cortico-cortical pathways when mice use their whiskers to discriminate between different objects or different locations. Within the primary and secondary somatosensory cortices (S1 and S2, respectively) as well as vibrissae motor cortex (M1), intermingled functional representations of touch, whisking, and licking were found, which partially re-organized during discrimination learning. These findings provide first glimpses of cortico-cortical communication but emphasize that for understanding the complete process of discrimination it will be crucial to elucidate the details of how neural processing is coordinated across brain-wide neuronal networks including the S1-S2-M1 triangle and cortical areas beyond.
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Affiliation(s)
- Fritjof Helmchen
- Laboratory of Neural Circuit Dynamics, Brain Research Institute, University of Zurich, Switzerland.
| | - Ariel Gilad
- Laboratory of Neural Circuit Dynamics, Brain Research Institute, University of Zurich, Switzerland
| | - Jerry L Chen
- Laboratory of Neural Circuit Dynamics, Brain Research Institute, University of Zurich, Switzerland
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49
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Bale MR, Maravall M. Organization of sensory feature selectivity in the whisker system. Neuroscience 2017; 368:70-80. [PMID: 28918260 PMCID: PMC5798594 DOI: 10.1016/j.neuroscience.2017.09.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 08/25/2017] [Accepted: 09/05/2017] [Indexed: 12/14/2022]
Abstract
Neurons in the whisker system are selective to spatial and dynamical properties – features – of sensory stimuli. At each stage of the pathway, different neurons encode distinct features, generating a rich population representation. Whisker touch is robustly represented; neurons respond to touch-driven fast fluctuations in forces at the whisker base. Cortical neurons have more complex and context-dependent selectivity than subcortical, e.g., to collective whisker motion. Understanding how these signals are integrated to construct whisker-mediated percepts requires further research.
Our sensory receptors are faced with an onslaught of different environmental inputs. Each sensory event or encounter with an object involves a distinct combination of physical energy sources impinging upon receptors. In the rodent whisker system, each primary afferent neuron located in the trigeminal ganglion innervates and responds to a single whisker and encodes a distinct set of physical stimulus properties – features – corresponding to changes in whisker angle and shape and the consequent forces acting on the whisker follicle. Here we review the nature of the features encoded by successive stages of processing along the whisker pathway. At each stage different neurons respond to distinct features, such that the population as a whole represents diverse properties. Different neuronal types also have distinct feature selectivity. Thus, neurons at the same stage of processing and responding to the same whisker nevertheless play different roles in representing objects contacted by the whisker. This diversity, combined with the precise timing and high reliability of responses, enables populations at each stage to represent a wide range of stimuli. Cortical neurons respond to more complex stimulus properties – such as correlated motion across whiskers – than those at early subcortical stages. Temporal integration along the pathway is comparatively weak: neurons up to barrel cortex (BC) are sensitive mainly to fast (tens of milliseconds) fluctuations in whisker motion. The topographic organization of whisker sensitivity is paralleled by systematic organization of neuronal selectivity to certain other physical features, but selectivity to touch and to dynamic stimulus properties is distributed in “salt-and-pepper” fashion.
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Affiliation(s)
- Michael R Bale
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom
| | - Miguel Maravall
- Sussex Neuroscience, School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom.
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50
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Abstract
A fundamental question in the investigation of any sensory system is what physical signals drive its sensory neurons during natural behavior. Surprisingly, in the whisker system, it is only recently that answers to this question have emerged. Here, we review the key developments, focussing mainly on the first stage of the ascending pathway - the primary whisker afferents (PWAs). We first consider a biomechanical framework, which describes the fundamental mechanical forces acting on the whiskers during active sensation. We then discuss technical progress that has allowed such mechanical variables to be estimated in awake, behaving animals. We discuss past electrophysiological evidence concerning how PWAs function and reinterpret it within the biomechanical framework. Finally, we consider recent studies of PWAs in awake, behaving animals and compare the results to related studies of the cortex. We argue that understanding 'what the whiskers tell the brain' sheds valuable light on the computational functions of downstream neural circuits, in particular, the barrel cortex.
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